Slide protractor



R. ABARE.

SLIDE PHOTHACTO-R.

APPLlcMloN man APR. 1s. 1921.

1,417,878, Patented 4May 3o, 1922.

I '5 a M760/'a INVENTOR WITNESS:

ROY ARABE, 0F CiZY, NE?? YORK.

STADE TROTRACTOR.

jig/1 3 F575?, Specification of Application filed April 1S,

T 0 @ZZ iii/om may conce/'ur lle it known that if., Pier Anania, a citizen ot the United States, residing at Chazy, in the county ot Clinton and ccitate ot lNew York, have invente-d new and uset'ul lmprovements in Slide Protractors, of which the following is a specification.

This invention relates to improven'ients in protractors, the general object oit the invention being to provide means iter 'facilitating the drawing ot lines of angles by means ot a pivoted ruler cooperating' with a scale on the arc part ot the device.

Another object oi" the invention is to provide a sight hole at the pivotal point ot the ruler so that the device may be placed with the pivotal. point at the center of: a scale.

A still further object oit the invention is to provide means 'tor holding the ruler in adjusted position.

This invention also consists in certain other features ot construction and in the combination an-d arrangement ot the several parts, to be hereinafter fully described, illustrated in the accompanying drawings and specilically pointed out in the appended claim.

In describing my invention in detail, reterence will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which Figure 1 is a plan view oi the invention.

Figure 2 is a section on line 2--2 et Fig;- ure 1.

Figures 3 and -ft are detail views.

As shown in these views the 'trame 1 consists ott the arc-shaped part 2 and the straight part 3, the arc-shaped part carrying; the scale 4l; and the straight part havin the inwardly extending central enlargement having an opening- 'therein and to which the stepped socket member 6 is secured with its socket over the opening. The socket in said member is screw threaded to receive the threaded thumb bolt 7. The slide or ruler 8 consists of the central piece 9 hitting within the space within the frame, said piece beingl of tapered shape with its small end adjacent the enlargement 5; the piece 10 secured to the small end ot piece 9 and having an opening' 11 for receiving the thumb screw, and the piece 12 secured to the outer end oit the piece 9 and overlapping the scale carrying part. This piece 12 is provided with a reduced extension 13 forming a hanv'l's Ententatented May 30, 1922.

resi. semi ivo. 452,165.

and carries a thumb screw 1s for enga-9,'- .r the part 2 so that the slide may be campeddn adjusted position. The outer end ot piece 9 is recessed, as at 15, and the inner edge ot piece 2 is recessed, as at 1G, these recessed portions overlapping` each other as shown. Thus when the clamping,` screw 1-1- isscrewed in the slide is eil'ectuallv locked te the trame. Piece 10 is provided withoiiset portions, as shown, so that the opening will rest upon the top of socket 6 and the thumb bolt r' is provided with a central opening 1'? actingF as a sight opening` so that the device can be properly positioned. Attention is called te thefact that if the lines forming; the edges oft the piece 9 were extended they would converge at the center opening 17 which is the the anis ot the said piece.

it will be seen that the parts are so arranged that the slide 8 can be moved beyond the scale so that a line can be drawn parallel to the outer edge of part 3.

By my invention lines of angles can be easily and quickly drawn by simply moving' the slide 8 to the degree on the scale at which the angle is to be drawn in relation to another line. After the slide 8 has been adjusted it is secured in adjusted position by the thumb nut lil.

My device can be use-d with a T-square as the outer edge et ipart 3 can be placed against the T-square and the slide moved to secure the desired angle. By spacing' the inner edge ot the part 3 from the 180"V line the slide can be moved into a positionto rule a line parallel to the T-square and this also allows the use of the upper edge ot the slide in ruling;v lines et a degree less than the width ol the slide.

The sight opening in the thumb bolt 7 permits the device to be properly positioned over circles and arcs.

lt is thought from the 'foregoing' description that the advantages and novel features ot my invention will be readily apparent.

l desire it to be understood that I may make changes in the construction and in the combination and arrangement of the several parts, provided that such changes tall within the scope et the appended claim.

That I claim is A device or' the class described comprising a frame including` an arc-shaped scale carrying' part and a straight part connecting the ends oi' the arc-s aped part, said straight part having an inwardly extending `centrally arranged enlargement, a stepped ruler and aro-shaped part having overlapping portions7 the ruler having its other end l0 passing over and extending beyond the areshaped part, a thumb bolt Carried by said other end and engaging the are-shaped part and a handle formed on said extending part.

In testimony whereof I afIiX my signature. l5

ROY ABARE. 

